Stapler



FIG. 1 is a side, top, perspective view of the stapler with stapler tray and stapler base thereof shown in phantom;

FIG. 2 is a right side view thereof, the left side view thereof being a mirror image thereof;

FIG. 3 is a front view thereof;

FIG. 4 is a rear view thereof;

FIG. 5 is a top view thereof; and,

FIG. 6 is a bottom view thereof.

The broken lines shown in the drawings form no part of the claimed design. 

The ornamental design for a stapler, as shown and described. 